Reverberation unit assembly



a Sheets-Sheet 1 Sept. 22, 1964 w. R. SCHREIER REVERBERATION UNIT ASSEMBLY Filed April 26, 1962 p 1964 w. R. SCHREIER 3,150,335

REVERBERATION UNIT ASSEMBLY Filed April 26, 1962 s Sheets-$heet 2 INVENTOR:

Sept. 22, 1964 w. R. SCHREIER 3,150,335

REVERBERATION UNIT ASSEMBLY Filed April 26, 1962 s Sheets-Sheet s 91 U2 =25 95 i :25 92 S52 90 INVENTOR.

MWZW

United States Patent 3,150,335 REVERBERATION UNIT ASSEMBLY Wilford R. Schreier, Bensenville, 11]., assignor to Hammond Organ Company, Chicago, 111., a corporation of Delaware Filed Apr. 26, I962, Ser. No. 194,743 Claims. (Cl. 333-30) This invention relates in general to reverberation units for use with musical instruments, such as, either organs, radios or phonographs, and more particularly relates to an improved and more economical reverberation unit assembly.

Reverberation units generally comprise several coil springs which serve as transmission lines to convey signals in different time intervals to an output circuit for the purpose of simulating the acoustical effect of an auditorium. In such a unit there must be provided a signal generating assembly or driver comprising an input coil at one end of the spring. The input coil responds to an input electrical signal for controlling a tiny magnet attached to the adjacent end of the respective transmission lines. This introduces a corresponding mechanical wave into the transmission line which is sensed by a signal receiving assembly or pickup at the other end of the line. The pickup assembly comprises another magnet and coil which respond to the transmitted mechanical wave by providing an output electrical signal having a delayed interval dependent on the length of the spring and the rate of wave transmission. This output signal is then applied through suitable amplifying devices to an output transducer, such as a loud speaker, for the purpose of simulating the etlect described above.

The construction of such a reverberation unit usually incorporates several transmission lines of different characteristics in order to provide the different delay periods. In addition, the springs comprising the transmission lines must be arranged so that they are held in precise positions under tension with adjacent turns spaced apart, while at the same time they are isolated from the supporting structure. The construction of the unit is further complicated by the need to securely and simply position the tiny magnets adjacent the spring ends in a magnetic circuit having a precise gap with the circuit being furnished by a coil and pole piece assembly to which electrical connections must be facilely established.

It is therefore an object of the present invention to provide an improved reverberation unit assembly.

It is another object of the invention to provide an improved component design for a reverberation unit to permit a more facile and accurate assembly of the components.

It is still another object of the present invention to provide driver and pickup assemblies of substantially identical construction for use in a reverberation unit.

It is still a further object of the present invention to permit the transmission lines of a reverberation unit to be assembled separately from the driver and pickup assemblies and to be interchangeably assembled with ease to either the driver or pickup assemblies.

It is yet a further object of the present invention to provide reverberation unit driver or pickup assemblies having interchangeable components.

Other objects together with the features of the present invention will become apparent on examination of the following specification, claims and drawings, wherein:

FIG. 1 is an elevational view of the reverberation unit assembly;

FIG. 1a is an end view of the assembly shown in FIG. 1 With'certain details omitted;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1;

3,150,335 Patented Sept. 22, 1964 FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along the line 44 in FIG. 3;

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 3;

FIG. 6 is a sectional view taken along the line 6--6 in FIG. 3;

FIG. 7 is an exploded perspective view of the magnet and pole piece assembly; and

FIG. 8 is a sectional view illustrating the relationship between the coil, pole pieces and magnets.

In the drawings, the reverberation unit assembly is indicated by the reference character 10'. It comprises a channel member 12, a pair of transmission lines 14 and 16, a driver unit assembly 18 and a pickup unit assembly 20. The channel member 12 comprises opposite longitudinal side walls 22 and a back wall 23 therebetween. Each wall 22 is provided with apertures adjacent the pickup and driver assemblies for receiving the ends of respective coiled springs 24-24c. The springs 24-240 serve to suspend the reverberation unit 10 from a suitable mounting channel 25 for isolating the unit 10 from extraneous vibrations as explained in an application Serial No. 190,444, filed simultaneously herewith by William C. Laube, Jr. a

The driver and pickup units 15 and 2d are substantially identically constructed and dimensioned. Each includes an integrally formed case 26 having a pair of spaced apart depending L-shaped lugs 27 that extend through the back wall 23 as best seen in FIGS. 4 and 5 and project towards each other. A shoulder 28 on each lug limits the downward movement of the case. A leaf spring 3-1) is inserted between the respective lugs 27 along the lower side of wall 23 to seat the respective cases 26 in position. An angle stop 32 on the leaf spring engages the edge of Wall 23 as seen best in FIGS. 2 and 3, while a detent 33 engages an aperture in wall 23 to control the position of spring 30 and prevents its shifting. In addition, a ground strip 36 is inserted between the shoulders 28 and the top of wall 23 and is held firmly engaged against the wall 23 when clip 30 is inserted.

Each case 26 comprises a generally rectangular main body 38 having side faces 40, a front face 42, a back face 4-4, a top face 36, and a bottom face 48 from which the lugs 27 depend. A groove 50 in both the top and bottom faces extends back from the front face 42 towards the rear of the body 38 and a sloping stop element 52 having a vertical rear wall 53 is located in each groove as best seen in FIGS. 4- and 5.

The body 38 is provided with a deep substantially rectangularly shaped recess 54 in its front face 42. The recess 54 has side walls 55 intersected by vertical stop Walls 56. In the posterior portion of the recess 54 as seen in FIGS. 3 and 5, the vertical walls converge and a narrow aperture 58 connects the recess 54 to the back face 44 of the body. The aperture 58 is adapted to receive a connector strip 6% which extends through the recess 54 for the purpose of enabling electrical connections to be extended to'a coil 62. The coil 62 comprises part of a coil and pole piece assembly 64 adapted to be received in the recess 54 and in a pair of horizontal slots 66.

A horizontal slot 66 connects each side of the recess 54 with the side faces 49 of the body 38 for a predetermined distance from the front 'face 42. Each slot 66 is defined by flat upper and lower wall portions 68 from the front face 42 to a position intermediate the slot ends and then by arcuate top and bottom wall portions '70 which terminate at a stop wall 72 as best seen in FIG. 6. A narrow horizontal passageway 74 connects each slot 66 through the wall 72 to the back face 44 where the respective passageways terminate in a circular opening 76. Narrow recesses 77 aligned crosswise to the passageway 7 4 extend inwardly from the opening 76.

The coil and pole piece assemblies 64, as best seen in FIGS. 7 and 8, each comprise a bobbin 78 on which the coil 62 is wound in a conventional manner. The bobbin 7 8 has a rectangular passageway 3d therein and generally rectangular spool heads 82. A pair of pole pieces 84 are aech adapted to be engaged on a respective spool head 82 and each has a core portion as for engagement in the passageway 86.

The pole pieces 84 each comprise an elongate web 88 of magnetic material and the respective core portions 86 depend therefrom adjacent the transverse axis of the web and to one side thereof. An L-shaped flange 9% is provided at opposite ends of each pole piece and each flange has an arm 92 extending in opposing directions. The core portions 86 are inserted through spool heads 32 into opposite ends of passageway SE and in abutting relationship. The webs 88 are thus supported so that the arms 92 on one pole piece are in a more closely spaced relationship to an arm on the other pole piece than the pole piece webs. This reduces the area of flux leakage to that of arms 92 since only these areas are in close proximity to each other.

The spacing between respective arms 92- defines the gaps 3 of identical magnetic circuits and a tiny cylindrical magnet 94 at the end of each transmission line is located in each of the gaps. The magnets 94 each have an axial dimension substantially the same as the transverse dimension of the associated arms 92. It will be noted that the magnets 94 intersect the confined main flux path in the limited area traversed by arms 92 so that maximum signal emciency is achieved. In addition, the construction enables the gaps for the magnets at each end of both transmission lines to be effectively defined by a single pair of pole pieces and that these are all interchangeable.

It will be noted that each of the spool heads 82 is provided with a boss 98 along one end and that a recess 100 is provided in one end of each boss. Each recess 160 is adapted to receive respective arms 162 of the connector strip 69. The connector strip 60 is a flat elongate insulating plate 193 upon which is alfixed a pair of thin conductive layers 194 to which respective leads 106 of the coil are extended at lugs 107. The strip 60 has top and bottom stop portions 108 which abut the back of recess 54 when the coil and pole piece assembly 64 is inserted in recess 54. A tab portion 110 on the connector strip 66 extends through aperture 58 for the purpose of extending external electrical leads 112 to the coil. The leads 112' are positioned by a tab 114 that is staked onto wall 23.

The magnets 94 each have a central aperture in which a stepped tube 116 is inserted and cemented thereto. Each stepped tube 116 has a portion which is cemented to and crimped about a respective straight end 118 of a coil spring 120 or 122. The springs 126 and 122 each form a part of a respective transmission line 14 or 16. Each transmission line comprises two springs 120 or 122 respectively joined in the center of the line by an eyelet, for example, and connected at opposite ends to the magnets 94. The springs 12% or 122 are joined so that their windings are of opposite direction for the purpose of suppressing undesired vibrational modes.

It will be noted that although the springs of each transmission line are of identical length that the springs 122 of the transmission line 16 have a larger helix diameter than springs 120. Thus the springs of each line are wound to the same length with their turns in compressive relationship so that adjacent turns are normally touching. When assembled to the driver and pickup assemblies, the springs are stretched to separate the turns and the smaller diameter line 14 will of course transmit higher frequencies than the larger diameter line 16. However, in the range where the frequency transmitted by line 16 begins to fall off substantially, little acoustical effect is lost since in that range the single line 14 contributes sufficient reverberation effect.

Due to the step in the tube 116, a shoulder is formed which serves as a stop for a flattened end of a support wire 124 inserted partially therethrough as best seen in FIG. 6. The support wire 124 is extended through a rubber damping disc 126 and its other end is fastened along one diameter of an anchor disc 128 which serves as a bayonet connection as will be explained. Thus each transmission line 14 and 16 is a self-contained subassem bly comprising a pair of coiled springs 12d or 122 joined in the center of the line and having at each end a magnet 94, support Wire 124, damping disc 126 and anchor disc 12%.

To assemble the reverberation unit, a coil and pole piece assembly 64 is inserted in recess 54 in each case 26 with the tab projecting from the rear of the case. The ground strip 36 which has an elongated leg 132 extending towards the front face 42 and this is bent over and inserted between the lower pole piece and associated spool head before the assembly 64 is inserted in recess 54. Each case 26 is mounted on the channel 12 and held thereto by the leaf spring 36 either before or after the assembly 64 is inserted in recess 54, but in either event the walls 55 and 56 in recess 54 serve to control the position of the assembly 64.

The transmission lines 14 and 16 are assembled to the driver and pickup assemblies 18 and 20 by inserting the anchor disc 128 at one end of each transmission line through the passageway 74 after first passing the damping disc 126 along the angular face of arcuate walls 70. On passing therethrough and being aligned with circular opening 76 each anchor disc 128 is given a slight rotational movement and a slight pull thereon enables the anchor disc 128 to be seated in the recesses 77 to form a bayonet connection. Since the anchor disc 123 is then no longer aligned with the passageway 74, it cannot be pulled back through it so that one end of each transmission line is held in position. The disc 128 at the other end of each transmission line is then inserted through a passageway 74 in either the driver or pickup means as the case may be in the same fashion. Alternatively, of course, the transmission lines may be assembled to the cases 26 before the coil and pole piece assemblies 64 are inserted in recess 54.

The distance between the two ends of passageways 74 is calculated to just stretch the springs so that their turns are separated by an identical amount with the turns having a low helix angle to insure the proper propagation of the transmitted waves while at the same time the total spring length is held short. Thus, by the positioning of the cases 26 the correct spacing between the turns can be easily achieved. The magnets 94 then lie in the gaps 93 formed between a respective pair of arms 92 of the pole pieces.

In order to properly position and secure the pole pieces with respect to the magnets 94 while securing the coil and pole piece assembly 64 and in order to maintain the damping discs 126 properly positioned, a spring clip 134 is used to complete the positioning of the assembly. The clip 134 is generally U-shaped with the ends of the side legs 135 having ring shaped slotted right angle arms 136 thereon. In addition, a pair of wings 137 are provided at the end of each leg 135 and in the same plane, but projecting back therefrom at a transverse angle.

The back leg 138 of the clip 134 is provided with respective upwardly and downwardly projecting tines 139 and L-shaped arms 140. Each arm 140 has a locking bend 142 at the end thereof.

The clip 134 is assembled to the case 2.6 by inserting the side legs 135 together with wings 137 in the recess 54 while arms 14%) engage grooves 50. The slots in ring shaped arms 136 permit the arms to engage over the wire 124 between the magnets 94 and damping discs 126. As the clip 134 is pressed back, the arms 136 move the damping discs 126 through slots 66 between the arcuate Wall portions 70 and 72 to properly seat the same. At the same time the Wings 137 press the webs 84 of the pole pieces against the respective upper and lower walls of recess 54 to size the gap 93 therebetween. Simultaneously the walls 56 serve as stops for the arms 90 so that the pole pieces are positioned properly with respect to the magnets 94.

The tines 139 serve to apply pressure against the coil and pole piece assembly 64 and when the locking bend 140 on the clip passes over the vertical wall 53 of the stop 52, the assembly is securely held in position.

A rectangular resilient shielding element 142 is slipped over the front of the driver unit case 26 preferably before the transmission'lines 14 and 16 are assembled thereto. The element 142 has a set of ears 143 which engage around a tab 144 protruding from the sides of each case so that the element 142 is properly seated and supported. The element 142 additionally seats the legs 132 of the ground strip 36 against the bottom face 48 of the case so that it is in no danger of entanglement.

There has been described one embodiment of my invention, and since this embodiment is capable of many adaptations and modifications, there is appended hereto a series of claims for accurately setting forth the limitations of the invention.

I claim:

1. A reverberation unit for delaying a signal being transmitted to a signal output circuit, the improvement comprising a pair of transmission lines each including coiled springs, an anchor disc carried at each end of each line and along the axis of the respective line, a magnet fixedly carried adjacent opposite ends of each line, a damping element carried between each magnet and each anchor disc and axially movable relative to the respective line, a coil and pole piece assembly for the magnets at respective ends of each transmission line, a pair of cases each having a recess in one face thereof for receiving a respective coil and pole piece assembly, wall sections in said recesses defining limit positions for said pole pieces, a pair of longitudinal passageways in each case positioned between a respective side of said recess and a respective side of said case and adapted to have an anchor disc on either line passed therethrough only if said disc is aligned in a particular plane, means at the end of each passageway for holding said anchor discs out of said plane to prevent their return through said passageways whereby the distance between said means on the respective cases determines the stretched length of said springs and the position of said magnets, a spring clip element adapted to be inserted in said recess and arranged to securely position said pole pieces against said limit walls and in alignment with the respective magnets for forming a flux field therefor while moving said damping elements to a predetermined position.

2. A reverberation unit for introducing a time delay in a signal being transmitted to a signal output circuit, the improvement comprising a pair of transmission lines each comprising a coiled spring, an anchor disc carried adjacent each end of each line and along the axis of said springs, a magnet fixedly carried between each anchor disc and each spring, a pair of coil and pole piece assemblies with each assembly defining a flux gap for each magnet at either end of said line, a pair of cases each having a recess in one face thereof for receiving a respective coil and pole piece assembly, a pair of longitudinal passage ways extending along opposite sides of each case and adapted to have an anchor disc on each line passed there through only if said anchor disc is aligned for one plane, means at the end of each passageway for holding said anchor discs out of alignment with said plane to prevent their being returned through said passageways whereby the distance between said means on the respective cases determines the length of said springs in said unit and the position of said magnets, and wall sections in each recess defining the limit positions of said coil and pole piece assemblies and arranged to position said magnetic gaps astride respective magnets.

3. A reverberation unit for introducing a time delay in a signal being transmited to a signal output circuit, the improvement comprising a pair of transmission lines each comprising a coiled spring, an anchor disc carried adjacent each end of each line and along the axis of said springs, a magnet fixedly carried between each anchor disc and each spring, a pair of coil and pole piece assemblies with each assembly having a pair of pole pieces extending transversely to the axis of said lines and each having an L-shaped flange at opposite ends and a transverse core section adapted to be received inopposite ends of said bobbin for placing each L-shaped flange on one pole piece in spaced apart alignment with a respective L- shaped flange on the other pole piece, a pair of cases each having a recess in one face thereof for receiving a respective coil and pole piece assembly, a pair of longitudinal passageways extending along opposite sides of each case and adapted to have an anchor disc on each line passed therethrough only if said anchor disc is aligned for one plane, means at the end of each passageway for holding said anchor discs out of alignment with said plane to prevent their being returned through said passageways whereby the distance between said means on the respective cases determines the length of said springs in said unit and the position of said magnets, and wall sections in each recess defining the limit positions of said pole pieces and arranged to align respective spaced apart flanges astride respective magnets.

4. A reverberation unit for introducing a time delay in a signal being transmitted to a signal output circuit, the improvement comprising a pair of transmission lines each comprising a coiled spring of identical length, an anchor disc carried adjacent each end of each line and along the axis of said springs, a magnet fixedly carried between each anchor disc and each spring, a damping element carried between each magnet and each disc and axially movable with respect thereto, a pair of coil and pole piece assemblies with each assembly having a pair of pole pieces 1 extending transversely to the axis of said lines and each having an L-shaped flange at opposite ends and a transverse core section adapted to be received in opposite ends of said bobbin for placing each L-shaped flange on one pole piece in spaced apart alignment with a respective L- shaped flange on the other pole piece, a pair of cases each having a recess in one face thereof for receiving a respective coil and pole piece assembly, a pair of longitudinal passageways extending along opposite sides of each case and adapted to have an anchor disc on each line passed therethrough only if said anchor disc is aligned for one plane, means at the end of each passageway for holding said anchor discs out of alignment with said plane to prevent their being returned through said passageways whereby the distance between said means on the respective cases determines the length of said springs in said unit and the position of said magnets, wall sections in each recess defining the limit positions of said pole pieces and arranged to align respective spaced apart flanges astride a respective magnet, and means adapted to lock said coil and pole piece assemblies against said limit walls and for holding said damping elements in predetermined positions.

5. A reverberation unit for use in introducing a time delay in a signal being transmitted to a signal output circuit, the improvement comprising a pair of transmission lines each of identical length, said transmission lines each comprising a coil spring with the spring of one line having a larger helix diameter than the spring of the other line and with both springs being of the same length when free of tension, a magnet carried on each end of each spring, a damper element carried adjacent each magnet and axially movable with respect to each spring, an anchor disc carried adjacent each damper element and along the axis of said springs, a pair of bobbins each having a coil wound thereon, a pair of pole pieces for each bobbin each having an Lsshaped flange at opposite ends thereof and a transverse core section adapted to be received in opposite ends of said bobbin for placing each L-shaped flange on one pole piece in spaced apart alignment with a respective L-shaped flange on the other pole piece, a pair of cases each having a recess in one face thereof for receiving said coil, bobbin and pole pieces, wall sections in said recesses defining the limit positions of said pole pieces, a pair of longitudinal passageways extending on either side of said recess to the back face of said .case and adapted to have an anchor disc on each line passed therethrough, means at the end of each passageway for preventing said anchor discs from being returned through said passageways whereby the distance between said means on the respective cases determines the stretched length of said springs and the position of said magnets, a spring clip elemerit adapted to be inserted in said recess and arranged to securely position said pole pieces against said limit walls and with respective aligned flanges in alignment with respective magnets for forming a flux field therefor while simultaneously moving said damper elements to a predetermined position.

References Cited in the file of this patent UNITED STATES PATENTS 1,654,123 Hartley Dec. 27, 1927 1,678,116 Harrison July 24, 1928 1,719,484 Norton July 2, 1929 1,852,795 Wegel Apr. 5, 1932 2,211,205 2 Hammond Aug. 13, 1940 2,230,836 Hammond Feb. 4,1941 2,810,888 George Oct. 22, 1957 2,967,447 Hanert Ian. 10, 1961 3,092,792 Daniel June 4, 1963 

1. A REVERBERATION UNIT FOR DELAYING A SIGNAL BEING TRANSMITTED TO A SIGNAL OUTPUT CIRCUIT, THE IMPROVEMENT COMPRISING A PAIR OF TRANSMISSION LINES EACH INCLUDING COILED SPRINGS, AN ANCHOR DISC CARRIED AT EACH END OF EACH LINE AND ALONG THE AXIS OF THE RESPECTIVE LINE, A MAGNET FIXEDLY CARRIED ADJACENT OPPOSITE ENDS OF EACH LINE, A DAMPING ELEMENT CARRIED BETWEEN EACH MAGNET AND EACH ANCHOR DISC AND AXIALLY MOVABLE RELATIVE TO THE RESPECTIVE LINE, A COIL AND POLE PIECE ASSEMBLY FOR THE MAGNETS AT RESPECTIVE ENDS OF EACH TRANSMISSION LINE, A PAIR OF CASES EACH HAVING A RECESS IN ONE FACE THEREOF FOR RECEIVING A RESPECTIVE COIL AND POLE PIECE ASSEMBLY, WALL SECTIONS IN SAID RECESSES DEFINING LIMIT POSITIONS FOR SAID POLE PIECES, A PAIR OF LONGITUDINAL PASSAGEWAYS IN EACH CASE POSITIONED BETWEEN A RESPECTIVE SIDE OF SAID RECESS AND A RESPECTIVE SIDE OF SAID CASE AND ADAPTED TO HAVE AN ANCHOR DISC ON EITHER LINE PASSED THERETHROUGH ONLY IF SAID DISC IS ALIGNED IN A PARTICULAR PLANE, MEANS AT THE END OF EACH PASSAGEWAY FOR HOLDING SAID ANCHOR DISCS OUT OF SAID PLANE TO PREVENT THEIR RETURN THROUGH SAID PASSAGEWAYS WHEREBY THE DISTANCE BETWEEN SAID MEANS ON THE RESPECTIVE CASES DETERMINES THE STRETCHED LENGTH OF SAID SPRINGS AND THE POSITION OF SAID MAGNETS, A SPRING CLIP ELEMENT ADAPTED TO BE INSERTED IN SAID RECESS AND ARRANGED TO SECURELY POSITION SAID POLE PIECES AGAINST SAID LIMIT WALLS AND IN ALIGNMENT WITH THE RESPECTIVE MAGNETS FOR FORMING A FLUX FIELD THEREFOR WHILE MOVING SAID DAMPING ELEMENTS TO A PREDETERMINED POSITION. 